1. Field of the Invention
The present invention relates to a forming machine for forming a meandering loop winding used as a stator winding in a motor and to a method of forming the meandering loop winding.
2. Description of the Related Art
As a hybrid powered vehicle motor or an electric vehicle motor, the permanent magnet type alternating current synchronous motor or brushless DC motor in which permanent magnets are used in a rotor is widely used. As one of this type of motors, a permanent magnet type three-phase synchronous motor having a stator in which windings on a concentrated winding mode are wound around stator cores provided respectively for three phases (U phase, V phase, and W phase) so as to perform three-phase driving of a rotor having permanent magnets by the stator has been known, as for example described in Japanese Patent Laid-open No. Hei 11-299137.
In addition, a permanent magnet type three-phase synchronous motor having a stator in which windings for three phases (U phase, V phase, and W phase) are wound in wavy forms by disposing them in the manner of threadingly extending between teeth (claw poles) adjacent to each other in the circumferential direction so as to perform three-phase driving of a rotor by the stator has been known, as for example described in Japanese Patent Laid-open No. 2002-165396.
In the above-mentioned three-phase synchronous motors according to the related art, the windings are needed on the basis of each of the three phases. Therefore, it is difficult to suppress an increase in the number of component parts required to constitute the stator, and much labor is needed for winding the respective windings for the three phases. Moreover, in the stator having the windings on the wave winding mode, it is difficult to enhance the winding occupation factor between the adjacent teeth. Further, it is difficult to reduce the size in the axial direction of the motor by reducing the height at the coil end, in order to enhance the mountability onto a vehicle or the like.
In order to solve these problems in the related art, the present applicant has previously proposed a motor stator in which stator rings for three phases and loop windings for two phases are alternately disposed in the manner of sequentially stacking along a direction parallel to the axis and in which each of the loop windings is provided with a plurality of meandering parts so as to increase the magnetic flux generated by the stator (refer to Japanese Patent Application No. 2005-306778).
The stator in the permanent magnet type three-phase synchronous motor or claw pole motor according to the previous patent application mentioned above is configured by use of the loop windings having a plurality of meandering parts. However, such a loop winding having meandering parts was not generally used in the past, and, therefore, establishment of a method for forming such a meandering loop winding is being desired.